Stop to use __NetBSD_Prereq__ in pkgsrc

Hi,
The __NetBSD_Prereq__ macro is incompatible with after/before 4.99.3
(NetBSD-4 was re-branched from 4.99.4)
* http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/sys/param.h.diff?r1=1.241&r2=1.242
It should not be used in pkgsrc, at least, until netbsd-3 is EOL.
(pkglint should check it?)
Currently used in following patches:
devel/gdb/patches/patch-as
net/coda/patches/patch-ac
net/xorp/patches/patch-ab (PR 39705)
security/sfs/patches/patch-bv (PR 38051)
sysutils/radeontool/patches/patch-aa
sysutils/monit/patches/patch-ab
--
"Of course I love NetBSD":-)
OBATA Akio / obache%NetBSD.org@localhost